American equity markets closed the week of March 2 under notable pressure as investors processed an unusual combination of macro stresses: an active military conflict in the Persian Gulf driving oil toward 14-month highs, and a domestic tariff regime already pushing factory-gate prices to multi-year peaks. The Dow Jones Industrial Average declined 1.28% over the week, making it the weakest of the major US indices, while the S&P 500 fell 0.44%, according to SIB Global Markets data. The Nasdaq, weighted toward technology and less directly exposed to energy input costs, outperformed on a relative basis but still finished with a marginal loss.

The market's reaction reflects what analysts are increasingly describing as a dual supply shock — a combination not seen since the early 1970s, when an Arab oil embargo and wage-price spirals compressed real returns across asset classes for an extended period. The parallel is imperfect but structurally resonant: the 15% global tariff regime has imposed a persistent cost shock on goods-producing sectors, and the Iran conflict's energy price spike is now layering a second impulse onto an inflation picture that had already become more stubborn than the Federal Reserve would prefer.

Energy: The New Cost Floor

Brent crude settled at $81.40 per barrel on March 3 — its highest close since January 2025 and up 4.7% in a single session — after surging approximately 10% on the opening day of US-Israeli strikes against Iran on Sunday March 1. Year-to-date gains now stand at approximately 19% for Brent and 17% for WTI. For sectors with significant energy exposure — airlines, chemicals, trucking, plastics manufacturing — the move represents a meaningful compression of operating margins that could begin appearing in first-quarter earnings reports. For the broader context on what is driving those oil price levels and what a Strait of Hormuz closure would mean, see analysis of the global energy market context.

The energy cost escalation is arriving at a particularly difficult moment for consumer-facing companies. Walmart issued what has been described as a "Tariff Cliff" warning to investors, noting that its inventory buffers — built up ahead of the tariff implementation to avoid immediate pass-through — are now exhausted. The retailer warned of an immediate 3% increase in general merchandise prices as a direct result of tariff cost pass-through, a figure that predates any additional inflation from elevated energy costs. With an estimated 70% of its merchandise sourced or dependent on global supply chains affected by the tariff regime, Walmart's guidance effectively signals a new, higher price floor for large-format general merchandise retail.

Corporate Cost Warnings: GM and Caterpillar

General Motors disclosed in its most recent guidance that 2026 operating costs could swell by approximately $4 billion as a result of steel and aluminium tariff-related cost increases. The figure represents a significant headwind for a company already managing elevated capital expenditure requirements from its electric vehicle transition programme. Caterpillar, whose heavy equipment manufacturing has significant steel content, separately reported a 9% decline in operating profit attributable to approximately $1.03 billion in steel and aluminium tariff headwinds — a figure that analysts noted will compound if energy costs sustain at current levels, given the significant energy intensity of heavy manufacturing.

These disclosures matter for index-level performance because both GM and Caterpillar are Dow Jones components. The Dow's 1.28% weekly decline — its worst performance versus the S&P in recent weeks — partly reflects the heavier weighting of industrial and manufacturing components in that index versus the technology-heavy S&P 500 and Nasdaq. The sector rotation implications are clear: investors are reducing exposure to goods manufacturers with high tariff and energy cost exposure while maintaining or adding positions in defence contractors, energy producers, and technology companies with limited physical goods exposure.

The ISM Signal and the Fed's Dilemma

February ISM manufacturing data, released before the Iran conflict escalated, showed US factory-gate prices running at near a 3.5-year high according to Reuters. That reading reflected purely tariff-driven cost pressure. The March ISM, which will incorporate energy price inputs from the conflict's first weeks, is expected to show further price escalation — a reading that will add to the Federal Reserve's policy dilemma.

The Fed currently faces a set of conditions that monetary policy tools are ill-equipped to address simultaneously. Rate hikes to contain inflation risk crushing a goods sector already under tariff pressure and an equity market that has absorbed significant multiple compression. Rate cuts to support growth risk validating the stagflationary narrative that markets are beginning to price. Treasury Secretary Bessent has signalled the possibility of a further 15% tariff escalation on select imports, a move that would add a third layer of cost pressure to an economy already managing the existing tariff regime and the emerging energy shock.

The diplomatic dimension compounds the uncertainty. European allies' refusal to endorse US-Israeli strikes — and the resulting intra-NATO tension — creates additional unpredictability around the conflict's duration and potential escalation scenarios. As analysis of Europe's diplomatic response makes clear, the absence of a coherent allied strategy for conflict termination means markets cannot price a near-term de-escalation with any confidence.

Forward-Looking: Payrolls, Fed, and Earnings Risk

The nonfarm payrolls report due imminently represents the next significant data point for the Fed and for equity markets. A strong payrolls number would reduce the case for pre-emptive rate cuts but could also anchor inflation expectations at a level that makes the dual supply shock more durable. A weak payrolls print would heighten stagflationary concerns — a combination of rising prices and slowing employment growth that historically has limited the Fed's room to manoeuvre and compressed equity valuations.

First-quarter earnings season, which begins in April, will provide the first comprehensive look at how corporate America has absorbed the combined effects of the tariff regime and the energy shock. Companies with high energy input costs, global supply chain exposure, and limited pricing power are most at risk of earnings disappointment. Defence, energy production, and select technology sub-sectors are positioned to benefit from the current environment. The coming weeks will test whether the index-level performance of the past week represents a transitory correction or the beginning of a more sustained re-rating of equity risk in an era of structurally higher supply-side inflation.